The invention relates generally to the processing of photosensitive material.
More particularly, the invention relates to the processing of a band of photosensitive material by drawing the band through one or more processing tanks via a conveyor belt.
A known apparatus for processing a band of photosensitive material has a series of processing tanks. A conveyor belt passes through the various tanks and is provided with a clamp which is designed to engage the leading end of the band. This allows the conveyor belt to draw the band through the tanks for processing. The clamp engages the leading end of the band in such a manner that the latter travels in parallelism with the belt.
The clamp is held on the conveyor belt by friction. To this end, the clamp is provided with a pair of hook-like gripping or engaging elements which embrace, and are in frictional engagement with, the marginal portions of the belt. The gripping elements are spaced from one another transversely, and define an opening of width smaller than that of the belt. The clamp is mounted on the belt by bending the latter so that the marginal portions of the belt approach one another to a distance smaller than the width of the opening defined by the gripping elements. This allows the marginal portions to be introduced into the opening to thereby engage the gripping elements. Bending of the belt is accomplished using cooperating male and female dies which act in a direction normal to the plane of the belt.
An apparatus of the above type is disclosed, for example, in West German Pat. No. 25 12 836. The female die is here in the form of a roller configurated as a hyperboloid of one sheet while the male die is constituted by a pressure roller. When a clamp is to be mounted on the conveyor belt, the pressure roller urges the belt into the depression of the hyperboloid roller. This causes the belt to be bent to such an extent that the marginal portions of the belt move towards one another until the distance between them is less than the width of the opening defined by the gripping elements of the clamp. The clamp is supported by a holder preparatory to being mounted on the belt and, once the belt has been bent, the holder is moved towards the belt so that the marginal portions of the latter can enter the opening between the gripping elements. The pressure roller is now withdrawn thereby permitting the belt to straighten itself. Since the width of the belt is slightly larger than the width of the space inside the gripping elements, the belt retains some elastic deformation. This deformation causes the clamp to be secured to and drawn along by the belt through the agency of frictional forces.
Movement of the clamp towards the belt after bending increases the time required for attachment of the clamp to the belt. Moreover, since such movement is accomplished using a separately controlled holder for the clamp, the cost of the apparatus is increased.